CVE-2019-12529: Canonical Ubuntu Linux

Medium severity, CVSS 5.9. EPSS: 8.1% chance of exploitation in the next 30 days.

An issue was discovered in Squid 2.x through 2.7.STABLE9, 3.x through 3.5.28, and 4.x through 4.7. When Squid is configured to use Basic Authentication, the Proxy-Authorization header is parsed via uudecode. uudecode determines how many bytes will be decoded by iterating over the input and checking its table. The length is then used to start decoding the string. There are no checks to ensure that the length it calculates isn't greater than the input buffer. This leads to adjacent memory being decoded as well. An attacker would not be able to retrieve the decoded data unless the Squid maintainer had configured the display of usernames on error pages.

Affected products

• Canonical Ubuntu Linux: version 12.04 only; version 16.04 only; version 18.04 only; version 19.04 only
• Debian Debian Linux: version 8.0 only; version 9.0 only; version 10.0 only
• Fedoraproject Fedora: version 29 only
• Opensuse Leap: version 15.0 only; version 15.1 only
• Squid-Cache Squid: from 2.0, before 2.7 (fixed in 2.7); from 3.0, up to and including 3.5.28; from 4.0, up to and including 4.7; version 2.7 only

Published 2019-07-11. Last modified 2026-06-17.